Campaigners lost their bid to overturn a ban on doctors helping seriously ill people to die in England and Wales on Wednesday.
The case was brought by Paul Lamb, who was paralysed in a road accident 20 years ago and now requires 24-hour care. He now wants the legal right to end his life with the help of a medic.
He lodged the case alongside Jane Nicklinson, whose husband Tony had Locked-in Syndrome but died in 2012, a week after losing a previous legal battle to secure the right to die.
Their lawyers had argued that a ban on assisted suicide was incompatible with the right to respect for private and family life enshrined in the European Convention on Human Rights.
While the Supreme Court in London did not rule in their favour, five of the nine senior judges said they did have the power to declare that a blanket ban on assisted suicide was incompatible with the convention.
Two went further, saying they would have made such a ruling.
"I am very proud of myself. I know it is going to change," Lamb said after the judgement.
The court also dismissed a challenge from a severely disabled man identified only as Martin that the chief prosecutor for England and Wales should rewrite guidance on prosecutions relating to a similar issue.
Currently, people who help others to die face jail sentences of up to 14 years.
But there have been a string of legal challenges to the status quo in recent years amid growing pressure for a change in the law, which is resisted by religious groups.
The House of Lords—Britain's unelected second chamber of parliament—is to debate a bill that would legalise assisted dying next month but it has little chance of becoming law.